Currying facts for kids

Currying is a cool trick used in mathematics and computer science. It's a way to change a function that usually takes several inputs (called arguments) into a series of smaller functions. Each of these new functions takes just one input at a time.

This idea helps make computer programs simpler and easier to understand. It's named after a mathematician named Haskell Brooks Curry. Two other mathematicians, Moses Schönfinkel and Gottlob Frege, also helped develop the ideas behind it. Currying is often used in something called Lambda calculus, which is a way to study functions. Some programming languages, like ML and Haskell, are even designed so that functions can only take one input, making currying a very natural part of how they work.

What is Currying?

Imagine you have a machine that needs three ingredients to make a cake: flour, sugar, and eggs. Normally, you'd put all three in at once. Currying is like changing that machine so you first put in the flour, then you get a new machine that only needs sugar. After you add the sugar, you get another new machine that just needs eggs. Finally, after adding the eggs, you get your cake!

In computer terms, a function might need several pieces of information to do its job. Currying breaks down that big job into smaller steps. Each step gives you a new function that's waiting for the next piece of information.

Why is it called Currying?

This technique is named after an American mathematician and logician named Haskell Brooks Curry. He did a lot of important work in the 1920s and 1930s on how functions work and how they can be combined. Even though other mathematicians like Moses Schönfinkel and Gottlob Frege had similar ideas earlier, Curry's work helped make the concept more widely known in computer science.

How does Currying work?

Let's say you have a function that adds three numbers together: `add(x, y, z)`. If you use currying, you would change it into something like this:

• First, a function that takes `x`.
• This function then gives you a new function that takes `y`.
• That second function then gives you another new function that takes `z`.
• Finally, after `z` is given, you get the total sum.

It looks like this: `add(x)(y)(z)`. Each step returns a new function until all the inputs are given. This can make code cleaner and more flexible.

Where is Currying used?

Currying is a very important idea in a type of programming called Functional programming. This style of programming focuses on building programs using functions that work like mathematical functions.

• Functional Programming Languages: Many modern programming languages that support functional programming, like Haskell, Scala, and JavaScript, use currying. In Haskell, for example, all functions are automatically "curried" by default.
• Making Code Reusable: Currying helps create more flexible and reusable pieces of code. You can create specialized versions of functions by giving them some inputs and then saving the new, partially-filled function for later use.
• Simplifying Complex Tasks: By breaking down functions into smaller, single-input steps, it can make complex tasks easier to manage and understand.

See also

In Spanish: Currificación para niños